Process for coloring polyolefinic textile materials



United States atent 1 of Delaware No Drawing. Filed Aug. 25, 1959, Ser. No. 835,839 2 Claims. (Cl. 8-55) This invention relates to the dyeing or coloring of polyolefin textile materials, such as fibers, threads, yarns, woven fabrics, knitted fabrics or other fibrous textile forms. Such materials may be composed of one or more of the polymers known as polyolefins, for example, low-density polyethylene, high-density polyethylene, and polypropylene.

Substantial amounts of dyestuffs cannot be applied to polyolefin fibers by conventional methods for dyeing textile materials. it has been proposed that certain classes of dyestuffs can be applied to polyolefin materials by the use of specific organic solvents instead of the water used in conventional dyeing processes but this method requires the handling of large quantities of volatile and inflammable solvents, and must be performed in specially constructed apparatus.

It is also known that polyolefin materials may be dyed by the use of a dilute Water dispersion of a solution of certain dyestuffs in organic solvents, at elevated temperatures. It has been found, however, that the amount of color which can be applied by this method is limited, so that deep shades cannot be obtained on polyolefin materials composed of fine fibers, e.g. fibers of the order of 3 to 10 denier.

Polyolefin materials may also be colored by incorporating suitable pigments into the polymer before the.

fibers are extruded. This, however, imposes many limitations and disadvantages which are well known to the textile industry. For example, it is in many cases desirable to weave the fabrics of uncclored yarn and to dye them after weaving. It has heretofore not been possible to dye polyolefin fabrics in a full range of colors on conventional textile processing equipment.

The principal object of the present invention is to provide a novel process for coloring polyolefinic textile materials which obviates the disadvantages of prior procedures for coloring these materials. Another object of the in vention is the provision of a process for dyeing polyolefin fibers or the like which permits satisfactory dyeing over a full range of colors with conventional textile processing apparatus. Other advantages and objects of the invention will also be hereinafter apparent.

Broadly stated, the present process comprises the application by padding of an emulsion of a solvent solution of a solvent-soluble dyestuff in water to a polyolefin textile material, e.g. polyolefin fibers or fabric. Desirably, the padding operation is carried out at room temperature, e.g. -25 C., although higher temperatures not exceeding the temperature at which substantial vaporization occurs, may also be used.

It has been found that by the use of an emulsion containing a large proportion of solvent solution of dyestuif, according to the invention, suiiicient color can be applied to obtain as deep a shade as desired. The use of a padding operation, which comprises passing the textile material through a bath of the color emulsion and immediately thereafter through a pair of rolls which effect a uniform and thorough impregnation of the fabric by the emulsion, has the advantage of requiring relatively small amounts of dyestuif and solvent, as compared to other dyeing methods. The greatest economy of materials is thereby achieved, and at the same time, there is avoided the necessity for handling large quantities of 3,040,076 Patented July 24, 1962 volatile solvents. The operation can be carried out on conventional textile padding equipment.

The solvents which may be employed comprise; liquid hydrocarbons of both the aliphatic and aromatic series, and halogen derivatives thereof. The classes of organic compounds encompassed are saturated and unsaturated aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, aromatic hydrocarbons including alkyl derivatives thereof, and halogenated compounds derived from any of the above clasess of hydrocarbons by substituting chlorine, bromine, or iodine for one or more of the hydrogens thereon. Among the suitable solvents may be mentioned hexane, decane, cyclohexane, methyl cyclohexane, diisobutylene, benzene, toluene, the isomers of xylene, ethylbenzene, tetralin, tetrachloroethane, trichloroethylene, and chlorobenzene. Mixtures of two or more compounds of the above classes may be employed.

Dyestufls which may be employed preferably belong to one of the classes of dyes known as disperse dyes, basic dyes, and solvent dyesgbut may be any dyestuif or mixture thereof, having any appreciable solubility in aliphatic or aromatic hydrocarbons or their halogen derivatives. Desirably, the dyestuff should be sufficiently soluble to give a solvent solution comprising about 1 to 5% by weight of dyestuif. The following products, with identifying Color Index Numbers are listed as representative dyestuffs suitable for use herein:

DISPERSE DYES Color Index No.

Disperse Yellow 1 10345 Disperse Orange 1 11080 Disperse Red 41 11040 Disperse Blue 3 61505 BASIC DYES Auramine 41000 Safranine 50240 Victoria Blue 44045 Bismarck Brown 210103 SOLVENT DYES Solvent Yellow 2 11020 Solvent Yellow 7 11800 Solvent Red 24 26105 Solvent Blue 36 The water emulsion to be employed herein should contain between 30% and 70% by volume of the organic solvent. Emulsification of the solvent in water may be efiected by the use of an appropriate emulsifying or dispersing agent, preferably of the non-ionic type, such as Triton X100. Other suitable emulsifying or dispersing agents include: Igepal CO-880, Tergitol Non-ionic NPX.

Subsequent to the application by padding of the color emulsion, it is advantageous to allow the solvent solution to penetrate into the fiber in order to give a more uniform dyeing. This may be accomplished by allowing the fabric to stand at room temperature (Le. 2025 C.) in the wet condition for a period in excess of ten minutes, preferably for about one to two hours. During such (period of standing, it is desirable that the water and solvent not be permitted to evaporate from the fabric. Evaporation may be avoided by placing the fabric in a closed container or wrapping it in a suitable vapor impermeable material. Alternative to a period of standing at room temperature, the fabric may be subjected to elevated temperatures (e.g. 70 to C.) in a suitable vessel which is sealed to prevent any substantial evaporation of water and solvent. If desired, Water and solvent may be introduced into the vessel to maintain a saturated atmosphere of water and solvent vapor. Such treatment at elevated temperatures effects penetration of the fibers by color in a shorter time than does standing at room temperature. Thus, for example, the treatment at elevated temperatures may be completed in a period as short as five minutes with five to fifteen minutes usually preferred. It may be noted that in many instances a period of standing or exposure to elevated temperatures is not necessary to effect a satisfactory deposition of color.

Subsequent to the padding operation and any standing at room or elevated temperature, as above described, it is desirable to remove the water and solvent by evaporation. This may be accomplished on conventional textile drying equipment, and is preferably performed at a temperature between 100 C. and 150 C., but in any case at a temperature below that at which the properties of the polyolefin are adversely affected.

Following the drying, it is preferable to subject the fabric to a conventional textile scouring operation, which eifects removal of residual emulsifying agent and any dyestuff which is deposited loosely on the surface of the fabric.

The amount of emulsion padded on the textile material may be widely varied and will depend upon other operating factors such as the composition of the emulsion and the nature of the material being treated. Usually, however, the padding operation is such that the padded material is from 50 to 125% heavier than the prepadded material, i.e. the liquid pickup comprises from 50 to 125% by weight of the dry material.

The following examples illustrate, but do not limit, the invention described herein:

Example 1 A dyestulf emulsion was prepared by dissolving ten grams of Eastman Blue BNN (Color Index No. 61505), a disperse dye, in 250 ml. of commercial xylene. To this solution was added 250 ml. of water and 25 grams of Triton X 100 (registered trademark), a non-ionic emulsifying agent. The mixture was stirred vigorously 'until a uniform emulsion was obtained. This emulsion was padded onto a fabric woven of filament polypropylene yarns. Pickup amounted to 100% by weight of the dry fabric, The fabric was immediately rolled up and inserted into a container, which was then tightly closed, and allowed to stand for one hour. The fabric was then fastened to a frame to restrain it from shrinkage, and was dried in an oven at 140 C. 'It was then scoured in hot water and again dried. It was dyed a desirable full shade of blue.

Example 2 Ten grams of Du Pont oil Yellow N (Color Index No. 11020), ten grams of du Pont oil Blue A, and ten grams of Du Pont oil Red (Color "Index No. 26105) were dissolved in 200 ml. of commercial xylene. This solution was added to 150 ml. of water, 25 grams of Triton X-100 added, and the mixture agitated vigorously until a uniform emulsion was obtained. This emulsion was padded onto a fabric made of filament polypropylene. The fabric was placed in a closed container for a period of one hour, after which it was dried at 130 C., scoured in hot water, and again dried. It was dyed a desirable deep black.

4 Example 3 Example 4 Two grams of auramine (Color Index No. 41000) were suspended in 250 ml. of xylene, 250 ml. of water and 25 grams of Triton X-l00 added, and the mixture agitated until a uniform emulsion was obtained. This emulsion was padded onto a spun polypropylene fabric. The fabric was allowed to stand for one hour, and was then dried at 130 C., scoured and dried. It was dyed a desirable light yellow.

It will be appreciated that various modifications may be made in the invention described herein. Accordingly, the scope of the invention is defined in the following claims wherein I claim:

1. A process for coloring a polyolefiu textile material selected from the group consisting of polyethylene and polypropylene textile materials which comprises dissolving an essentially water-insoluble dyestuff in an organic solvent selected from the group consisting of hydrocarbon and halogenated hydrocarbon solvents to obtain a solvent solution containing 0.1 to 10% by weight of dyestutf; emulsifying said solvent solution in'water to form an emulsion in which water constitutes the continuous phase and the solvent solution the disperse phase, said emulsion containing from 30 to organic solvent by volume; padding said textile material with said emulsion at a temperature of about -2025 0.; allowing the padded material to stand at a temperature of 20 to C. without substantial evaporation of water and solvent therefrom for a period of at least ten minutes and drying said material at a temperature between 100 and C.

2. The process of claim 1 wherein the dyestuff is selected from the group consisting of disperse, basic and solvent dyes.

References Cited in the file of this patent UNITED STATES PATENTS 2,635,942 Thummel Apr. 21, 1953 2,828,180 Sertorio Mar. 25, 1958 2,864,816 Nicolaus et al Dec. 16, 1958 2,881,045 Mecco Apr. 7, 1959 OTHER REFERENCES American Dyestutf Reporter, Feb. 8, 1960, No. 3, pp. 41-44, Peirent et al. (Paper presented on May 15, 1959 before joint meeting of the Northern New England Section and the LTI Student Chapter, at M.I.T., Lowell, Mass).

Peirent et al.: Thesis, Lowell Technological Institute (1956), cited in American Dyestuff Reporter, Feb. 8, 1960, No. 3, pp. 41-44. 

1. A PROCESS FOR COLORING A POLYOLEFIN TEXTILE MATERIAL SELECTED FROM THE GROUP CONSISTING OF POLYETHYLENE AND POLYPROPYLENE TEXTILE MATERIALS WHICH COMPRISES DISSOLVING AN ESSENTIALLY WATER-INSOLUBLE DYESTUFF IN AN ORGANIC SOLVENT SELECTED FROM THE GROUP CONSISTING OF HYDROCARBON AND HALOGENATED HYDROCARBON SOLVENTS TO OBTAIN A SOLVENT SOLUTION CONTAINING 0.1 TO 10% BY WEIGHT OF DYESTUFF; EMULSIFYING SAID SOLVENT SOLUTION IN WATER TO FORM AN EMULSION IN WHICH WATER CONSTITUTES THE CONTINUOUS PHASE AND THE SOLVENT SOLUTION THE DISPERSE PHASE, SAID EMULSION CONTAINING FROM 30 TO 70% ORGANIC SOLVENT BY VOLUME; PADDING SAID TEXTILE MATERIAL WITH SAID EMULSION AT A TEMPERATURE OF ABOUT 20-25*C.; ALLOWING THE PADDED MATERIAL TO STAND AT A TEMPERATURE OF 20* TO 110*C. WITHOUT SUBSTANTIAL EVAPORATION OF WATER AND SOLVENT THEREFROM FOR A PERIOD OF AT LEAST TEN MINUTES AND DRYING SAID MATERIAL AT A TEMPERATURE BETWEEN 100* AND 150*C. 